Adding Vehicles to the Grid

The next power plant you rely on could be a wind farm in the rural west, or a bunch of solar panels on the local landfill, or a super-efficient natural gas facility built on the outskirts of town. Or it could be a Mini Cooper parked into your driveway.

Mark Elias/Bloomberg via Getty

It sounds far-fetched, especially when you consider their batteries are comparatively small, and need to be continually charged by power of the motor. And even with the souped-up batteries that power electric cars, those vehicles have limited range.

But if you look at it from another angle, it makes perfect sense. A certain amount of energy stored—that can be accessed on demand at a particular time and location—is equal to the same amount of energy produced.

At 4:00 p.m. on a hot summer day, lots of people turn on their air conditioning at the same time. The utility can meet that demand by firing up a power plant that has been sitting idle (hugely expensive), by purchasing power on the open market (very expensive), or by paying certain big customers to dial down their own usage, thus freeing up more capacity (less expensive). Or it can release energy that has been stored up (potentially less expensive).

There are efforts underway to do this on a large scale. In late September, Southern California Edison opened the nation’s largest battery-storage facility, which is capable of providing about 32 megawatts of capacity, which can power about 10,000 homes for an hour.

What do cars have to do with this? As every driver knows, car batteries are small, temporary power plants. And the batteries installed in all-electric vehicles pack a greater punch than typical car batteries. Most cars spend much of their lives parked. And so you could theoretically outfit a bunch of parked electric cars with two-way chargers, so they can suck in power and remain fully charged—and then dispense electricity quickly when called upon.

Several experiments in the emerging vehicle-to-grid sector are underway.

At the University of Delaware, professor Willett Kempton, is an evangelist for “grid-integrated vehicles” and here is the concept. As his website notes: “One properly designed electric-drive vehicle can put out over 10kW, the average draw of 10 houses.”

Willett oversaw a project in which the university, in partnership with power company NRG, rigged up nine electric vehicles with two-way charging systems. The vehicles, Mini Coopers in the main, had a combined output of about 100 kilowatts. The cars would draw electricity as needed, and were compensated for standing ready to discharge their combined wattage into the grid when asked. It worked —- from an engineering perspective and from a financial perspective. Each car brought in a monthly payment of about $110, as the Wall Street Journal reported. “We’re not earning enough money to get rich,” as Kempton told the Journal. But even so, “it earns more money than it cost to do it.”

So it is not surprising that a larger-scale vehicle-to-grid project is underway in Southern California. Los Angeles Air Force Base, as part of a larger Defense Department initiative, is setting up a system that would let 40 electric vehicles—from cars to vans and trucks—plug in and both receive and provide power. Software designed by the Lawrence Berkeley Laboratory will enable them to toggle quickly between receiving and providing electricity, depending on the demands of the system.

Adding vehicles to the grid could be a boon to vehicle and fleet owners in several ways. A 2012 study by scientists at he Massachusetts Institute of Technology concluded that if trucking fleets were to plug in fleets of electric vehicles overnight, they could reap revenues of between $900 and $1,400 annually per vehicle. And in many regions, the price of energy varies during the day—it becomes less expensive during the night, when fewer people are plugged in, and more expensive during peak hours. So in theory, car owners could buy low, by charging batteries at night, and then sell high, by discharging batteries during the day.